110 VERTBBHATES. 



in their, embankments are not carried on their tailsj as some say, 

 nor do the beavers use their tails as trowels for laying on the mud ; 

 the fact li eing that the stones and mud are carried between their 

 chin and fore-paws, and the mistake respecting the tail is evidently 

 caused by the slap that beavers give with that member when they 

 dive. In order that their pond may not be too deep, they always 

 leave an opening in the dam to let the water escape when it rises 

 above a certain height. They cut most of their food in the sum- 

 mer, taking care to choose trees above their houses, so that thj 

 stream floats them down to the place where they wish to use them. 

 They also lay up stores of food for the winter, by cutting a number 

 of green branches and sinking them near the door of their habi- 

 tations, where they are held firm by stones laid on the summit of 

 the heap. During the severe winter, their mud-built houses freeze 

 quite hard, and prevent the wolverine, their greatest enemy except 

 man, from breaking through and devouring the inmates. Every 

 year the beavers lay a fresh coating of mud upon their houses, so 

 that after the lapse of a few years the walls of the house are 

 several feet in thickness. Many of the houses are built close 

 together, but no two families can communicate with each other, 

 except by diving below the walls and rising inside their neighbors' 

 houses. 



The far of the Beaver is exceedingly valuable, especially 

 for the manufacture of hats, and is greatly sought after. The 

 hunting season is in winter, when the beavers are quietly in their 

 houses. The hunters, armed with spears, etc., break the tops of 

 the houses. The alarmed beavers instantly rush out and pass 

 under the ice to certain hiding-places in the bank. The hunter 

 then discovers the position of the hole in the bank by the sound 

 of bis spear struck against the ice ; he then breaks a hole and 

 spears the animal in its place of fancied security. A substance 

 called castor was formerly obtained from the Beaver and much 

 used in medicine, but is now discarded. 



The fur of the Beaver, like that of many other animals, 

 consists of a fine wool intermixed with long and stiff hairs. The 

 hairs are useless, but the peculiar construction of the fur causes 



